/*  $Revision: 9320 $
**
**  Do shell-style pattern matching for ?, \, [], and * characters.
**  Might not be robust in face of malformed patterns; e.g., "foo[a-"
**  could cause a segmentation violation.  It is 8bit clean.
**
**  Written by Rich $alz, mirror!rs, Wed Nov 26 19:03:17 EST 1986.
**  Rich $alz is now <rsalz@osf.org>.
**  April, 1991:  Replaced mutually-recursive calls with in-line code
**  for the star character.
**
**  Special thanks to Lars Mathiesen <thorinn@diku.dk> for the ABORT code.
**  This can greatly speed up failing wildcard patterns.  For example:
**	pattern: -*-*-*-*-*-*-12-*-*-*-m-*-*-*
**	text 1:	 -adobe-courier-bold-o-normal--12-120-75-75-m-70-iso8859-1
**	text 2:	 -adobe-courier-bold-o-normal--12-120-75-75-X-70-iso8859-1
**  Text 1 matches with 51 calls, while text 2 fails with 54 calls.  Without
**  the ABORT code, it takes 22310 calls to fail.  Ugh.  The following
**  explanation is from Lars:
**  The precondition that must be fulfilled is that DoMatch will consume
**  at least one character in text.  This is true if *p is neither '*' nor
**  '\0'.)  The last return has ABORT instead of FALSE to avoid quadratic
**  behaviour in cases like pattern "*a*b*c*d" with text "abcxxxxx".  With
**  FALSE, each star-loop has to run to the end of the text; with ABORT
**  only the last one does.
**
**  Once the control of one instance of DoMatch enters the star-loop, that
**  instance will return either TRUE or ABORT, and any calling instance
**  will therefore return immediately after (without calling recursively
**  again).  In effect, only one star-loop is ever active.  It would be
**  possible to modify the code to maintain this context explicitly,
**  eliminating all recursive calls at the cost of some complication and
**  loss of clarity (and the ABORT stuff seems to be unclear enough by
**  itself).  I think it would be unwise to try to get this into a
**  released version unless you have a good test data base to try it out
**  on.
*/

#define TRUE			1
#define FALSE			0
#define ABORT			-1

 /*
  * What character marks an inverted character class? 
  */
#define NEGATE_CLASS		'^'
 /*
  * Is "*" a common pattern? 
  */
#define OPTIMIZE_JUST_STAR
 /*
  * Do tar(1) matching rules, which ignore a trailing slash? 
  */
#undef MATCH_TAR_PATTERN

/*
**  Match text and p, return TRUE, FALSE, or ABORT.
*/
static int DoMatch(text, p)
register char *text;
register char *p;
{
    register int last;
    register int matched;
    register int reverse;

    for (; *p; text++, p++) {
        if (*text == '\0' && *p != '*')
            return ABORT;
        switch (*p) {
        case '\\':
            /*
             * Literal match with following character. 
             */
            p++;
            /*
             * FALLTHROUGH 
             */
        default:
            if (*text != *p)
                return FALSE;
            continue;
        case '?':
            /*
             * Match anything. 
             */
            continue;
        case '*':
            while (*++p == '*')
                /*
                 * Consecutive stars act just like one. 
                 */
                continue;
            if (*p == '\0')
                /*
                 * Trailing star matches everything. 
                 */
                return TRUE;
            while (*text)
                if ((matched = DoMatch(text++, p)) != FALSE)
                    return matched;
            return ABORT;
        case '[':
            reverse = p[1] == NEGATE_CLASS ? TRUE : FALSE;
            if (reverse)
                /*
                 * Inverted character class. 
                 */
                p++;
            matched = FALSE;
            if (p[1] == ']' || p[1] == '-')
                if (*++p == *text)
                    matched = TRUE;
            for (last = *p; *++p && *p != ']'; last = *p)
                /*
                 * This next line requires a good C compiler. 
                 */
                if (*p == '-' && p[1] != ']' ? *text <= *++p && *text >= last : *text == *p)
                    matched = TRUE;
            if (matched == reverse)
                return FALSE;
            continue;
        }
    }

#ifdef	MATCH_TAR_PATTERN
    if (*text == '/')
        return TRUE;
#endif                          /* MATCH_TAR_ATTERN */
    return *text == '\0';
}

/*
**  User-level routine.  Returns TRUE or FALSE.
*/
int wildmat(char *text, char *p)
{
#ifdef	OPTIMIZE_JUST_STAR
    if (p[0] == '*' && p[1] == '\0')
        return TRUE;
#endif                          /* OPTIMIZE_JUST_STAR */
    return DoMatch(text, p) == TRUE;
}

#if	defined(TEST)
#include <stdio.h>

int main()
{
    char p[80];
    char text[80];

    printf("Wildmat tester.  Enter pattern, then strings to test.\n");
    printf("A blank line gets prompts for a new pattern; a blank pattern\n");
    printf("exits the program.\n");

    for (;;) {
        printf("\nEnter pattern:  ");
        (void) fflush(stdout);
        if (fgets(p, 80, stdin) == NULL || p[0] == '\0')
            break;
        else {
            p[79] = 0;
            p[strlen(p) - 1] = 0;
        }
        for (;;) {
            printf("Enter text:  ");
            (void) fflush(stdout);
            if (fgets(text, 80, stdin) == NULL)
                exit(0);
            text[79] = '\0';
            text[strlen(text) - 1] = 0;
            if (text[0] == '\0')
                /*
                 * Blank line; go back and get a new pattern. 
                 */
                break;
            printf("      %s\n", wildmat(text, p) ? "YES" : "NO");
        }
    }

    exit(0);
    /*
     * NOTREACHED 
     */
}
#endif                          /* defined(TEST) */
